Insecticide toxicity associated with detoxification enzymes and genes related to transcription of cuticular melanization among color morphs of Asian citrus psyllid

Abstract

The Asian citrus psyllid (Diaphorina citri Kuwayama) is known to exhibit abdominal color polymorphisms. In the current study, susceptibility to four insecticides was compared among orange/yellow, blue/green and gray/brown color morphs of field collected D. citri. The LD values and 95% fiducial limits were quantified for each insecticide and color morph combination and ranged between 0.10 ng/μL (0.06-0.10) and 6.16 ng/μL (3.30-12.50). Second, we measured the detoxification enzyme activity levels of orange/yellow, blue/green and gray/brown color morphs for cytochrome P450, glutathione S-transferase, and general esterase. The mean P450 activity (equivalent units) was significantly lower in gray/brown (0.152 ± 0.006) and blue/green morphs (0.149 ± 0.005) than in the orange/yellow morphs (0.179 ± 0.008). GST activity (μmol/min/mg protein) was significantly lower in the orange/yellow morph (299.70 ±1.24) than gray/brown (350.86 ± 1.19) and blue/green (412.25 ± 1.37) morphs. The mean EST activity (μmol/min/mg protein) was significantly higher in blue/green (416.72 ± 5.12) and gray/brown morphs (362.19 ± 4.69) than in the orange/yellow morphs (282.56 ± 2.93). Additionally, we analyzed the relative expression of assortment genes involved in cuticular melanization and basal immunity. The transcripts of Dopa Decarboxylase and Tyrosine Hydroxylase were expressed higher in blue/green and gray/brown than orange/yellow morphs. The transcription results paralleled the susceptibility of D. citri to organophosphate, neonicotinoid and pyrethroid insecticides. GST and EST activity may also be correlated with low levels of insecticide susceptibility. Cuticular melanization could be a factor for the development of resistance to insecticides among different color morphs.

Volatile β-Ocimene Can Regulate Developmental Performance of Peach Aphid Myzus persicae Through Activation of Defense Responses in Chinese Cabbage Brassica pekinensis

“…Similar to CYP6CY3 , CYP4 is another key detoxification CYP family in insects ( Silva et al, 2012 ). In an insecticide-resistant morph of the Asian citrus psyllid Diaphorina citri Kuwayama, the gene expressions of CYP4 family members were significantly higher than those in the susceptible morph ( Chen et al, 2018 ). In addition to the CytP450-dependent detoxification system, we also found that feeding on β-ocimene-treated plants induced the expression of GST in aphids, which has been identified as being involved in the adaptation to plant defensive metabolites in various insect species, including M. persicae ( Francis et al, 2005 ).…”

Assessment of Variation in Feeding Behavior by Color Morph in the Asian citrus Psyllid (Diaphorina citri)

“…Physiological plasticity in insects can increase survival in the face of diverse environmental challenges (Chown 2001). In ACP, color polyphenism among genetically similar individuals has been linked to physiological states that differ in important life traits such as reproductive capacity, reproductive behavior, dispersal, resistance to insecticides, cold resistance, immunity, and interactions with microbes (e.g., CLas) (Tiwari et al 2013;Martini et al 2014;Stockton et al 2017;Hosseinzadeh et al 2019;Ibanez et al 2019;Chen et al 2019;Hosseinzadeh et al 2021;Martini et al 2021). However, associations between color morphology and feeding behavior have not been explored for all three ACP color types (blue-green, grey-brown, and yellow-orange), and investigations thus far have been limited to a single population of ACP collected in Florida (Ebert and Rogers 2020).…”

“…Even though the mechanisms behind color type shifts are not clear, ACP color morphs exhibit significant differences in reproductive potential (Ibanez et al 2019), reproductive behavior (Stockton et al 2017), dispersal capacity (Martini et al 2014), resistance to insecticides (Tiwari et al 2013;Chen et al 2019), cold resistance (Martini et al 2021), immunity (Hosseinzadeh et al 2021) and CLas acquisition and inoculation (Hosseinzadeh et al, 2019). Many of these metrics (e.g., reproduction, dispersal or immunity) are energetically demanding processes that may drive foraging and feeding behaviors required to obtain sufficient nutrients.…”

Comparative transcriptome analysis of thiamethoxam susceptible and resistant Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), using RNA‐sequencing

“…Cuticular thickening is not limited to the procuticle, and also occurs at the epicuticle layer (Balabanidou et al ., 2018). We found up‐regulation (>6×) of a Yellow gene, which is associated with pigmentation and waterproofing of the epicuticle (Chen et al ., 2019). Certain quinone metabolites are produced in the cuticle in the process of scleretization, which crosslink with CPs (Mun et al ., 2019).…”